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-   -   I've looked high and low - I can't seem to find it. (https://ecomodder.com/forum/showthread.php/ive-looked-high-low-i-cant-seem-find-6523.html)

Christ 12-24-2008 01:25 AM

I've looked high and low - I can't seem to find it.
 
Please keep in mind - this is still a pipe dream for me!

Preliminary goals for an EV that would fit my use are set to something like 50MPH (80km/h) steady, 55-60 peak (85-95km/h) with approx 50mile (80km) range.

What would I have to do/spend/build/kiss the backside of to make this happen in a ~1500lb car?

Some points to consider:

I'm going to be in need of a reversible engine, to save some weight and parasitic drag in the transmission, I'll be removing unnecessary gears.

I won't need vacuum assisted brakes, so no vacuum pumps for me. Heat will most likely be handled without the need for power from the vehicle as well.

I expect the vehicle to be mostly barren, but it will have an OEM CD/stereo setup with 4 speakers.

2 seats, b/c it's a CR-X. (1986 Si model.)

I will change all the lights to LED arrays. (Lowest energy solution for the headlights?)

Aero optimization will be considered as well.

I'm just looking at a cost vs. effect ratio here... I want to know what it's going to take, and if I'm thinking a little too far outside my limits for the project.

captainslug 12-24-2008 02:02 AM

Quote:

Originally Posted by Christ (Post 80145)
Preliminary goals for an EV that would fit my use are set to something like 50MPH (80km/h) steady, 55-60 peak (85-95km/h) with approx 50mile (80km) range.

It will get expensive, and fairly quickly at that.
From everything I've read, ranges above 30 miles (especially if you need to achieve them at highway speeds) will usually require higher drive voltages (84 volts or above). You will also need a more rare/expensive controller (or even a DIY one) in order to control the higher voltage motor.

Jeff McCabe's delicious Porsche 928 conversion has the specs you're after. Even if he chose a comparatively heavy chassis and ended up with a much higher top speed than what you're asking for, it's a good starting point for parts shopping.
http://www.evalbum.com/img/736/736c.jpg
Jeff McCabe's 1984 Porsche 928

The Triac runs at 144 volts with a 160ah pack resulting in 100 miles of range
The Triac Electric - 2009

120-144 volts with a 100ah pack coupled to a 9" 15-25hp motor will probably net the end result you're after. But that's just a guess based on the figures that I've seen.

Daox 12-24-2008 08:25 AM

I ran over the calculations a while back when I picked up a Paseo (fairly similar car) with a siezed engine. Here is what you need to look at.

It will take roughly 450 Wh to keep you going 60 mph. I know its not 55, these were my numbers. This is also a bit conservative of a number.

450 Wh * 45 mile range till batteries are totally dead = 20250 Wh battery pack capacity

20250 Wh * 2 = 40500 Wh pack so you don't go below 50% pack charge to retain good battery life

140 Ah * 12V deep cycle battery = 1680 Wh per battery This is a bit optimistic of a number. I've been told you won't get that much Ah out of a battery when discharging it as fast as you do in an EV.

40500 Wh desired pack capacity / 1680 Wh per battery = 24 batteries

These batteries weigh roughly 78 lbs a piece, so you're looking at adding 1872 lbs in batteries to the vehicle.

Now, you still have to find a 96V or better controller which is gonna cost you a fair amount (anything abouve 72V seems to go up fast). You also need a way to charge those 24 batteries.

Kinda sucks to run the numbers. I know I didn't like it, but thats what it is. I wish I had a job closer to home. I'd do it in a heartbeat.

bennelson 12-24-2008 06:57 PM

Doax's numbers sound about right.

I often have people say things to me like, "So what kind of range do you get on a charge on that thing, 100, 200 miles?"

Most people don't have a basic understanding of power, energy, and weight involved in a project like a home-built EV.

A 50 mile/55 mph is not a beginner conversion, it's a pretty solid vehicle that will take plenty of time and money to make happen. Take a look through the EV Album - EVAlbum: Build Questions

Page through a few of the vehicles listed there. Take careful note to compare the speed and range specs to the cost of conversion. Many of the high-end vehicles are labors of love, and cost a pretty penny.

Also, just get any information on electric conversions you can - hit the library, talk to people, find your local chapter of the Electric Auto Association, and show up at a few meetings.

A CRX would be a cool EV, but I don't think it would be practical for a longer range vehicle. Might be really slick with a small, high-voltage battery pack though!

Of people I personally know, the guy with the S10 Pickup conversion has a very nice truck. Once he's totally finished with it, it should have a pretty good range. His has somewhere around 24-26 batteries in it. Keep in mind that the CHARGER for his truck cost about the same as my entire car project.

Tom's Dodge Neon conversion is going to be great when finished. It will have 300 volts of batteries in it. Basically removing the back seat and filling the car with lead. Also, his car is AC, which is more efficient, and will have regenerative brakes too.

Inexpensive AND long-range don't seem to go well together in EV's. I am exploring the possibilities of a generator trailer, or using a bio-diesel or veggie oil vehicle for the longer trips, and the EV for the shorter ones.

One car seldom does everything you want it to.

Just think how many gallons of gasoline we could save if even a small percentage of people drove an EV every other day!

DifferentPointofView 12-24-2008 10:32 PM

Look up how they connected all those batteries for the AC Eboxx, That seemed to work fairly well, and get around 100 miles per charge (of course, probably VERY costly.)

order99 12-25-2008 01:41 AM

From what i've been told, you can have long range, high speed, and low cost-pick two. Not trying to discourage you, but i'm pretty sure that's just how it goes. With my beloved NiMHs locked up by Chevron and the Lithiums being (so far) hideously expensive, most DIY-ers are going with Lead Acid-and that means weight, which affects performance, which locks you into optimum Volt/Amp vs weight, etc. It gets pricey.

Christ, are you rural, suburban or urban? I have yet to produce an EV of any kind yet(need one more test before qualifying for my dream job-and a paycheck!) but when I do i'm going to try a powered Bicycle as my first EV. Since i'm strictly rural an EV Bike will be little more than a Proof of Concept toy, but if you have commutes/errands of under 30 miles a day, a decent Pedal Hybrid, Scooter or small Motorcycle EV could prove both useful and inexpensive. A 1or 2 HP motor would kill on a Powered Bicycle, Controllers are much cheaper-a 3.5 HP Golf Cart motor and a 36-48V controller would make a nice Scooter, etc. Also, any mistakes you make will be less expensive on the small scale, and good practice before the Full-sized conversions.

My own plan will be to make my cheap EV Pedal Hybrid, perhaps make it useful with a Booster Cart(Bike Trailer with extra Batteries in Parallel for more range, plus room for cargo), then later on try my hand at an ultralight, Medium-to-highway speed Trike with 40-50 miles per charge...imagine the Twike and the City-El having a kid, only engineered with Analog controls and Redneck Engineering tech from 1979 or so (gotta stick to what I know!).

Don't worry, i'll announce when i'm ready-give you all time to retreat to the safety of the Blast Shields... :D

Oh, you mentioned LEDs-those are great for brakes, running lights and turn signals, but check with DOT on the legality for headlights. Some states may or may not pass it on inspection.

order99 12-25-2008 01:51 AM

Oh, almost forgot:

BugE Main Page Earth for Earthlings

Relatively low-priced kit, can purchase piecemeal if you want to modify-about 40 MPH for 35 miles in stock configuration, engine/battery boosts get much better results on both. Due to modular kit construction, later upgrades to stock aren't bad!

I want something more enclosed and cargo-capable for a later project, and I won't spend that much for my initial 'room for errors' design-but it might be something you could use.

Geebee 12-25-2008 03:07 AM

Electric Trike 48 MPH - 'BentRider Online Forums
Maybe an option a 48 mph BugE

order99 12-25-2008 11:19 AM

Poor guy-gets his dream machine and then they tear up his road... :(

It's a pity he can't mod that Bug-E for off-roading...personally, I think he could, but since he'd end up covered in mud (open fairing) I could see why he didn't try.

jjackstone 12-25-2008 01:56 PM

Depends on your expense account. Check out the Metric Mind site for a good build description on a CRX.
Advanced electric vehicle conversion project
Good luck.
JJ


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